//--------------------------------------------------------------------------
// <copyright file="Encrypts.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <summary>Encrypts</summary>
//--------------------------------------------------------------------------
namespace MS.Msn.MediaSolutions.Common
{
    using System;
    using System.IO;
    using System.Text;
    using System.Collections;
    using System.Security.Cryptography;

    /// <summary>
    /// Reversible Encrypt
    /// </summary>
    public static class Encrypts
    {
        #region Reversible Encrypt

        /// <summary>
        /// Revs Encrypt Type
        /// </summary>
        public enum RevsEncryptType
        {
            /// <summary>
            /// 
            /// </summary>
            DES_Mixture,
            /// <summary>
            /// 
            /// </summary>
            DES_freeByteKey,
            /// <summary>
            /// 
            /// </summary>
            DES_8ByteKeyStanderdChar,
            /// <summary>
            /// 
            /// </summary>
            DES_8ByteKeyAllChar,
        };

        /// <summary>
        /// DES encrypt
        /// </summary>
        /// <param name="ToEncrypt">string to encrypt</param>
        /// <param name="EncryptKey">key</param>
        /// <param name="enType">methods:
        /// 1-any byte key, no other characters;
        /// 2-8 byte key, no other characters;
        /// 3-8 byte key, have other characters;
        /// default-both</param>
        /// <returns>encrypted string</returns>
        public static string RevsEncrypt(string ToEncrypt, string EncryptKey, RevsEncryptType enType)
        {
            if (EncryptKey != null)
            {
                string result = string.Empty;
                switch (enType)
                {
                    case RevsEncryptType.DES_freeByteKey:
                        result = EncryptDesFreeByteKey(ToEncrypt, EncryptKey);
                        break;

                    case RevsEncryptType.DES_8ByteKeyStanderdChar:
                        result = EncryptDesStanderdChar(ToEncrypt, EncryptKey.PadRight(8, '2'));
                        break;

                    case RevsEncryptType.DES_8ByteKeyAllChar:
                        result = EncryptDesAllChar(ToEncrypt, EncryptKey.PadRight(8, '3'));
                        break;

                    default:
                        if (EncryptKey.Length != 8)
                            result = EncryptDesFreeByteKey(EncryptDesAllChar(ToEncrypt, (EncryptKey.Length >= 8 ? EncryptKey.Substring(0, 8) : EncryptKey.PadRight(8, '0'))), EncryptKey);
                        else
                            result = EncryptDesStanderdChar(EncryptDesAllChar(ToEncrypt, EncryptKey), EncryptKey);
                        break;
                }
                return result;
            }
            else
            {
                throw new ArgumentNullException(Apps.GetArgNullExString("EncryptKey"));
            }
        }

        /// <summary>
        /// Encrypt
        /// </summary>
        /// <param name="ToEncrypt">string to encrypt</param>
        /// <param name="EncryptKey">key</param>
        /// <returns>DES_Mixture by default</returns>
        public static string RevsEncrypt(string ToEncrypt, string EncryptKey)
        {
            return RevsEncrypt(ToEncrypt, EncryptKey, RevsEncryptType.DES_Mixture);
        }

        /// <summary>
        /// DES decrypt
        /// </summary>
        /// <param name="ToDecrypt">string to decrypt</param>
        /// <param name="DecryptKey">key</param>
        /// <param name="deType">methods:
        /// 1-any byte key, no other characters;
        /// 2-8 byte key, no other characters;
        /// 3-8 byte key, have other characters;
        /// default-both</param>
        /// <returns>decrypted string</returns>
        public static string RevsDecrypt(string ToDecrypt, string DecryptKey, RevsEncryptType deType)
        {
            if (DecryptKey != null)
            {
                string result = string.Empty;
                switch (deType)
                {
                    case RevsEncryptType.DES_freeByteKey:
                        result = DecryptDesFreeByteKey(ToDecrypt, DecryptKey);
                        break;

                    case RevsEncryptType.DES_8ByteKeyStanderdChar:
                        result = DecryptDesStanderdChar(ToDecrypt, DecryptKey.PadRight(8, '2'));
                        break;

                    case RevsEncryptType.DES_8ByteKeyAllChar:
                        result = DecryptDesAllChar(ToDecrypt, DecryptKey.PadRight(8, '3'));
                        break;

                    default:
                        if (DecryptKey.Length != 8)
                            result = DecryptDesAllChar(DecryptDesFreeByteKey(ToDecrypt, DecryptKey), (DecryptKey.Length >= 8 ? DecryptKey.Substring(0, 8) : DecryptKey.PadRight(8, '0')));
                        else
                            result = DecryptDesAllChar(DecryptDesStanderdChar(ToDecrypt, DecryptKey), DecryptKey);
                        break;
                }
                return result;
            }
            else
            {
                throw new ArgumentNullException(Apps.GetArgNullExString("ToDecrypt"));
            }
        }

        /// <summary>
        /// DES decrypt
        /// </summary>
        /// <param name="ToDecrypt">string to decrypt</param>
        /// <param name="DecryptKey">key</param>
        /// <returns>DES_Mixture by default</returns>
        public static string RevsDecrypt(string ToDecrypt, string DecryptKey)
        {
            return RevsDecrypt(ToDecrypt, DecryptKey, RevsEncryptType.DES_Mixture);
        }

        /// <summary>
        /// DES Encrypt
        /// </summary>
        /// <param name="ToEncrypt">string to encrypt</param>
        /// <param name="EncryptKey">key</param>
        /// <returns>enctypted string</returns>
        private static string EncryptDesAllChar(string ToEncrypt, string EncryptKey)
        {
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            byte[] byKey = Encoding.UTF8.GetBytes(EncryptKey);

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.UTF8.GetBytes(ToEncrypt);

            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(byKey, IV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            return Convert.ToBase64String(ms.ToArray());
        }

        /// <summary>
        /// DES decrypt
        /// </summary>
        /// <param name="ToDecrypt">string to decrypt</param>
        /// <param name="DecryptKey">key</param>
        /// <returns>dectypted string</returns>
        private static string DecryptDesAllChar(string ToDecrypt, string DecryptKey)
        {
            byte[] byKey = Encoding.UTF8.GetBytes(DecryptKey);
            byte[] IV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            byte[] inputByteArray = Convert.FromBase64String(ToDecrypt);

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(byKey, IV), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            return Encoding.UTF8.GetString(ms.ToArray());
        }

        /// <summary>
        /// DES Encrypt
        /// </summary>
        /// <param name="ToEncrypt">string to encrypt</param>
        /// <param name="EncryptKey">key</param>
        /// <returns>enctypted string</returns>
        private static string EncryptDesStanderdChar(string ToEncrypt, string EncryptKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.UTF8.GetBytes(ToEncrypt);

            des.Key = ASCIIEncoding.ASCII.GetBytes(EncryptKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(EncryptKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            //Write the byte array into the crypto stream 
            //(It will end up in the memory stream) 
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            //Get the data back from the memory stream, and into a string 
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                //Format as hex 
                ret.AppendFormat("{0:X2}", b);
            }
            return ret.ToString();
        }

        /// <summary>
        /// DES decrypt
        /// </summary>
        /// <param name="ToDecrypt">string to decrypt</param>
        /// <param name="DecryptKey">key</param>
        /// <returns>dectypted string</returns>
        private static string DecryptDesStanderdChar(string ToDecrypt, string DecryptKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            //Put the input string into the byte array 
            byte[] inputByteArray = new byte[ToDecrypt.Length / 2];
            for (int x = 0; x < ToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(ToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(DecryptKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(DecryptKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

            //Flush the data through the crypto stream into the memory stream 
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            return Encoding.UTF8.GetString(ms.ToArray());
        }

        /// <summary>
        /// DES Encrypt
        /// </summary>
        /// <param name="ToEncrypt">string to encrypt</param>
        /// <param name="EncryptKey">key</param>
        /// <returns>enctypted string</returns>
        private static string EncryptDesFreeByteKey(string ToEncrypt, string EncryptKey)
        {
            if (string.IsNullOrEmpty(EncryptKey))
            {
                EncryptKey = "9aC3i0Df2W";
            }
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(ToEncrypt);
            byte[] keyByteArray = Encoding.Default.GetBytes(EncryptKey);
            byte[] sIV;
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            byte[] sKey = new byte[8];
            sIV = new byte[8];
            for (int i = 0; i < 8; i++)
                sKey[i] = hb[i];
            for (int i = 8; i < 16; i++)
                sIV[i - 8] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            cs.Close();
            ms.Close();
            return ret.ToString();
        }

        /// <summary>
        /// DES decrypt
        /// </summary>
        /// <param name="ToDecrypt">string to decrypt</param>
        /// <param name="DecryptKey">key</param>
        /// <returns>dectypted string</returns>
        private static string DecryptDesFreeByteKey(string ToDecrypt, string DecryptKey)
        {
            if (string.IsNullOrEmpty(DecryptKey))
            {
                DecryptKey = "9aC3i0Df2W";
            }
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = new byte[ToDecrypt.Length / 2];
            for (int x = 0; x < ToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(ToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }
            byte[] keyByteArray = Encoding.Default.GetBytes(DecryptKey);
            SHA1 ha = new SHA1Managed();
            byte[] hb = ha.ComputeHash(keyByteArray);
            byte[] sKey = new byte[8];
            byte[] sIV = new byte[8];
            for (int i = 0; i < 8; i++)
                sKey[i] = hb[i];
            for (int i = 8; i < 16; i++)
                sIV[i - 8] = hb[i];
            des.Key = sKey;
            des.IV = sIV;
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
        #endregion

        #region Hash Encrypt

        /// <summary>
        /// 
        /// </summary>
        /// <param name="txt"></param>
        /// <returns></returns>
        public static string HashShaString(string txt)
        {
            return HashShaString(txt, false);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="txt"></param>
        /// <param name="isLetter"></param>
        /// <returns></returns>
        public static string HashShaString(string txt, bool isLetter)
        {
            string rtval = string.Empty;

            using (Stream s = new MemoryStream(UTF8Encoding.Default.GetBytes(txt)))
            {
                SHA1CryptoServiceProvider shaCsp = new SHA1CryptoServiceProvider();
                byte[] buffer = shaCsp.ComputeHash(s);
                rtval = BitConverter.ToString(buffer);

                if (isLetter)
                {
                    rtval = rtval.Replace("-", string.Empty);
                }
            }

            return rtval;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="txt"></param>
        /// <returns></returns>
        public static string HashMd5String(string txt)
        {
            return HashMd5String(txt, false);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="txt"></param>
        /// <param name="isLetter"></param>
        /// <returns></returns>
        public static string HashMd5String(string txt, bool isLetter)
        {
            string rtval = string.Empty;

            using (Stream s = new MemoryStream(UTF8Encoding.Default.GetBytes(txt)))
            {
                MD5CryptoServiceProvider md5Csp = new MD5CryptoServiceProvider();
                byte[] buffer = md5Csp.ComputeHash(s);
                rtval = BitConverter.ToString(buffer);

                if (isLetter)
                {
                    rtval = rtval.Replace("-", string.Empty);
                }
            }

            return rtval;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="fileName"></param>
        /// <returns></returns>
        public static string HashMd5File(string fileName)
        {
            return HashMd5File(fileName, false);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="fileName"></param>
        /// <param name="isLetter"></param>
        /// <returns></returns>
        public static string HashMd5File(string fileName, bool isLetter)
        {
            string rtval = string.Empty;

            using (Stream s = new FileStream(fileName, FileMode.Open, FileAccess.Read))
            {
                MD5CryptoServiceProvider md5Csp = new MD5CryptoServiceProvider();
                byte[] buffer = md5Csp.ComputeHash(s);
                rtval = BitConverter.ToString(buffer);

                if (isLetter)
                {
                    rtval = rtval.Replace("-", string.Empty);
                }
            }

            return rtval;
        }

        #endregion

        #region Hash Encrypt - commented

        ////static state variables
        //private static UInt32 A;
        //private static UInt32 B;
        //private static UInt32 C;
        //private static UInt32 D;

        ////number of bits to rotate in tranforming
        //private const int S11 = 7;
        //private const int S12 = 12;
        //private const int S13 = 17;
        //private const int S14 = 22;
        //private const int S21 = 5;
        //private const int S22 = 9;
        //private const int S23 = 14;
        //private const int S24 = 20;
        //private const int S31 = 4;
        //private const int S32 = 11;
        //private const int S33 = 16;
        //private const int S34 = 23;
        //private const int S41 = 6;
        //private const int S42 = 10;
        //private const int S43 = 15;
        //private const int S44 = 21;

        ///// <summary>
        ///// 
        ///// </summary>
        ///// <param name="UnEncrypted"></param>
        ///// <returns></returns>
        //public static string HashSHAString(string UnEncrypted)
        //{
        //    return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(UnEncrypted, "SHA1");
        //}

        ///// <summary>
        ///// 
        ///// </summary>
        ///// <param name="UnEncrypted"></param>
        ///// <returns></returns>
        //public static string HashMD5String(string UnEncrypted)
        //{
        //    return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(UnEncrypted, "MD5");
        //}

        ///// <summary>
        ///// 
        ///// </summary>
        ///// <param name="UnEncrypted"></param>
        ///// <param name="isUpper"></param>
        ///// <returns></returns>
        //public static string HashMD5String(string UnEncrypted, bool isUpper)
        //{
        //    if (UnEncrypted != null)
        //    {
        //        char[] c = UnEncrypted.ToCharArray();
        //        byte[] b = new byte[c.Length];
        //        for (int i = 0; i < c.Length; i++)
        //        {
        //            b[i] = (byte)c[i];
        //        }
        //        byte[] digest = MD5Array(b);
        //        return ArrayToHexString(digest, isUpper);
        //    }
        //    else
        //    {
        //        throw new ArgumentNullException(Apps.GetArgNullExString("UnEncrypted"));
        //    }
        //}

        ///// <summary>
        ///// 
        ///// </summary>
        ///// <param name="fileName"></param>
        ///// <param name="isUpper"></param>
        ///// <returns></returns>
        //public static string HashMD5File(string fileName, bool isUpper)
        //{
        //    FileStream fs = File.Open(fileName, FileMode.Open, FileAccess.Read);
        //    byte[] array = new byte[fs.Length];
        //    fs.Read(array, 0, (int)fs.Length);
        //    byte[] digest = MD5Array(array);
        //    fs.Close();
        //    return ArrayToHexString(digest, isUpper);
        //}

        //private static string ArrayToHexString(byte[] array, bool isUpper)
        //{
        //    string format = (isUpper ? "X2" : "x2");
        //    StringBuilder hexString = new StringBuilder();
        //    foreach (byte b in array)
        //    {
        //        hexString.Append(b.ToString(format, Apps.DefaultCulture));
        //    }
        //    return hexString.ToString();
        //}

        // * F, G, H and I are basic MD5 functions.
        // * F(X,Y,Z) =(X&Y)|((~X)&Z)
        // * G(X,Y,Z) =(X&Z)|(Y&(~Z))
        // * H(X,Y,Z) =X^Y^Z
        // * I(X,Y,Z)=Y^(X|(~Z))
        // */
        //private static UInt32 F(UInt32 x, UInt32 y, UInt32 z)
        //{
        //    return (x & y) | ((~x) & z);
        //}
        //private static UInt32 G(UInt32 x, UInt32 y, UInt32 z)
        //{
        //    return (x & z) | (y & (~z));
        //}
        //private static UInt32 H(UInt32 x, UInt32 y, UInt32 z)
        //{
        //    return x ^ y ^ z;
        //}
        //private static UInt32 I(UInt32 x, UInt32 y, UInt32 z)
        //{
        //    return y ^ (x | (~z));
        //}

        // * FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
        // * Rotation is separate from addition to prevent recomputation.
        // */
        //private static void FF(ref UInt32 a, UInt32 b, UInt32 c, UInt32 d, UInt32 mj, int s, UInt32 ti)
        //{
        //    a = a + F(b, c, d) + mj + ti;
        //    a = a << s | a >> (32 - s);
        //    a += b;
        //}
        //private static void GG(ref UInt32 a, UInt32 b, UInt32 c, UInt32 d, UInt32 mj, int s, UInt32 ti)
        //{
        //    a = a + G(b, c, d) + mj + ti;
        //    a = a << s | a >> (32 - s);
        //    a += b;
        //}
        //private static void HH(ref UInt32 a, UInt32 b, UInt32 c, UInt32 d, UInt32 mj, int s, UInt32 ti)
        //{
        //    a = a + H(b, c, d) + mj + ti;
        //    a = a << s | a >> (32 - s);
        //    a += b;
        //}
        //private static void II(ref UInt32 a, UInt32 b, UInt32 c, UInt32 d, UInt32 mj, int s, UInt32 ti)
        //{
        //    a = a + I(b, c, d) + mj + ti;
        //    a = a << s | a >> (32 - s);
        //    a += b;
        //}

        //private static void MD5_Init()
        //{
        //    A = 0x67452301;  //in memory, this is 0x01234567
        //    B = 0xefcdab89;  //in memory, this is 0x89abcdef
        //    C = 0x98badcfe;  //in memory, this is 0xfedcba98
        //    D = 0x10325476;  //in memory, this is 0x76543210
        //}

        //private static UInt32[] MD5_Append(byte[] input)
        //{
        //    int zeros = 0;
        //    int ones = 1;
        //    int size = 0;
        //    int n = input.Length;
        //    int m = n % 64;
        //    if (m < 56)
        //    {
        //        zeros = 55 - m;
        //        size = n - m + 64;
        //    }
        //    else if (m == 56)
        //    {
        //        zeros = 0;
        //        ones = 0;
        //        size = n + 8;
        //    }
        //    else
        //    {
        //        zeros = 63 - m + 56;
        //        size = n + 64 - m + 64;
        //    }
        //    ArrayList bs = new ArrayList(input);
        //    if (ones == 1)
        //    {
        //        bs.Add((byte)0x80); // 0x80 = $10000000
        //    }
        //    for (int i = 0; i < zeros; i++)
        //    {
        //        bs.Add((byte)0);
        //    }
        //    UInt64 N = (UInt64)n * 8;
        //    byte h1 = (byte)(N & 0xFF);
        //    byte h2 = (byte)((N >> 8) & 0xFF);
        //    byte h3 = (byte)((N >> 16) & 0xFF);
        //    byte h4 = (byte)((N >> 24) & 0xFF);
        //    byte h5 = (byte)((N >> 32) & 0xFF);
        //    byte h6 = (byte)((N >> 40) & 0xFF);
        //    byte h7 = (byte)((N >> 48) & 0xFF);
        //    byte h8 = (byte)(N >> 56);
        //    bs.Add(h1);
        //    bs.Add(h2);
        //    bs.Add(h3);
        //    bs.Add(h4);
        //    bs.Add(h5);
        //    bs.Add(h6);
        //    bs.Add(h7);
        //    bs.Add(h8);
        //    byte[] ts = (byte[])bs.ToArray(typeof(byte));
        //    /* Decodes input (byte[]) into output (UInt32[]). Assumes len is
        //     * a multiple of 4.
        //     */
        //    UInt32[] output = new UInt32[size / 4];
        //    for (Int64 i = 0, j = 0; i < size; j++, i += 4)
        //    {
        //        output[j] = (UInt32)(ts[i] | ts[i + 1] << 8 | ts[i + 2] << 16 | ts[i + 3] << 24);
        //    }
        //    return output;
        //}

        //private static UInt32[] MD5_Trasform(UInt32[] x)
        //{
        //    UInt32 a, b, c, d;
        //    for (int k = 0; k < x.Length; k += 16)
        //    {
        //        a = A;
        //        b = B;
        //        c = C;
        //        d = D;

        //        /* Round 1 */
        //        FF(ref a, b, c, d, x[k + 0], S11, 0xd76aa478); /* 1 */
        //        FF(ref d, a, b, c, x[k + 1], S12, 0xe8c7b756); /* 2 */
        //        FF(ref c, d, a, b, x[k + 2], S13, 0x242070db); /* 3 */
        //        FF(ref b, c, d, a, x[k + 3], S14, 0xc1bdceee); /* 4 */
        //        FF(ref a, b, c, d, x[k + 4], S11, 0xf57c0faf); /* 5 */
        //        FF(ref d, a, b, c, x[k + 5], S12, 0x4787c62a); /* 6 */
        //        FF(ref c, d, a, b, x[k + 6], S13, 0xa8304613); /* 7 */
        //        FF(ref b, c, d, a, x[k + 7], S14, 0xfd469501); /* 8 */
        //        FF(ref a, b, c, d, x[k + 8], S11, 0x698098d8); /* 9 */
        //        FF(ref d, a, b, c, x[k + 9], S12, 0x8b44f7af); /* 10 */
        //        FF(ref c, d, a, b, x[k + 10], S13, 0xffff5bb1); /* 11 */
        //        FF(ref b, c, d, a, x[k + 11], S14, 0x895cd7be); /* 12 */
        //        FF(ref a, b, c, d, x[k + 12], S11, 0x6b901122); /* 13 */
        //        FF(ref d, a, b, c, x[k + 13], S12, 0xfd987193); /* 14 */
        //        FF(ref c, d, a, b, x[k + 14], S13, 0xa679438e); /* 15 */
        //        FF(ref b, c, d, a, x[k + 15], S14, 0x49b40821); /* 16 */
        //        /* Round 2 */
        //        GG(ref a, b, c, d, x[k + 1], S21, 0xf61e2562); /* 17 */
        //        GG(ref d, a, b, c, x[k + 6], S22, 0xc040b340); /* 18 */
        //        GG(ref c, d, a, b, x[k + 11], S23, 0x265e5a51); /* 19 */
        //        GG(ref b, c, d, a, x[k + 0], S24, 0xe9b6c7aa); /* 20 */
        //        GG(ref a, b, c, d, x[k + 5], S21, 0xd62f105d); /* 21 */
        //        GG(ref d, a, b, c, x[k + 10], S22, 0x2441453); /* 22 */
        //        GG(ref c, d, a, b, x[k + 15], S23, 0xd8a1e681); /* 23 */
        //        GG(ref b, c, d, a, x[k + 4], S24, 0xe7d3fbc8); /* 24 */
        //        GG(ref a, b, c, d, x[k + 9], S21, 0x21e1cde6); /* 25 */
        //        GG(ref d, a, b, c, x[k + 14], S22, 0xc33707d6); /* 26 */
        //        GG(ref c, d, a, b, x[k + 3], S23, 0xf4d50d87); /* 27 */
        //        GG(ref b, c, d, a, x[k + 8], S24, 0x455a14ed); /* 28 */
        //        GG(ref a, b, c, d, x[k + 13], S21, 0xa9e3e905); /* 29 */
        //        GG(ref d, a, b, c, x[k + 2], S22, 0xfcefa3f8); /* 30 */
        //        GG(ref c, d, a, b, x[k + 7], S23, 0x676f02d9); /* 31 */
        //        GG(ref b, c, d, a, x[k + 12], S24, 0x8d2a4c8a); /* 32 */
        //        /* Round 3 */
        //        HH(ref a, b, c, d, x[k + 5], S31, 0xfffa3942); /* 33 */
        //        HH(ref d, a, b, c, x[k + 8], S32, 0x8771f681); /* 34 */
        //        HH(ref c, d, a, b, x[k + 11], S33, 0x6d9d6122); /* 35 */
        //        HH(ref b, c, d, a, x[k + 14], S34, 0xfde5380c); /* 36 */
        //        HH(ref a, b, c, d, x[k + 1], S31, 0xa4beea44); /* 37 */
        //        HH(ref d, a, b, c, x[k + 4], S32, 0x4bdecfa9); /* 38 */
        //        HH(ref c, d, a, b, x[k + 7], S33, 0xf6bb4b60); /* 39 */
        //        HH(ref b, c, d, a, x[k + 10], S34, 0xbebfbc70); /* 40 */
        //        HH(ref a, b, c, d, x[k + 13], S31, 0x289b7ec6); /* 41 */
        //        HH(ref d, a, b, c, x[k + 0], S32, 0xeaa127fa); /* 42 */
        //        HH(ref c, d, a, b, x[k + 3], S33, 0xd4ef3085); /* 43 */
        //        HH(ref b, c, d, a, x[k + 6], S34, 0x4881d05); /* 44 */
        //        HH(ref a, b, c, d, x[k + 9], S31, 0xd9d4d039); /* 45 */
        //        HH(ref d, a, b, c, x[k + 12], S32, 0xe6db99e5); /* 46 */
        //        HH(ref c, d, a, b, x[k + 15], S33, 0x1fa27cf8); /* 47 */
        //        HH(ref b, c, d, a, x[k + 2], S34, 0xc4ac5665); /* 48 */
        //        /* Round 4 */
        //        II(ref a, b, c, d, x[k + 0], S41, 0xf4292244); /* 49 */
        //        II(ref d, a, b, c, x[k + 7], S42, 0x432aff97); /* 50 */
        //        II(ref c, d, a, b, x[k + 14], S43, 0xab9423a7); /* 51 */
        //        II(ref b, c, d, a, x[k + 5], S44, 0xfc93a039); /* 52 */
        //        II(ref a, b, c, d, x[k + 12], S41, 0x655b59c3); /* 53 */
        //        II(ref d, a, b, c, x[k + 3], S42, 0x8f0ccc92); /* 54 */
        //        II(ref c, d, a, b, x[k + 10], S43, 0xffeff47d); /* 55 */
        //        II(ref b, c, d, a, x[k + 1], S44, 0x85845dd1); /* 56 */
        //        II(ref a, b, c, d, x[k + 8], S41, 0x6fa87e4f); /* 57 */
        //        II(ref d, a, b, c, x[k + 15], S42, 0xfe2ce6e0); /* 58 */
        //        II(ref c, d, a, b, x[k + 6], S43, 0xa3014314); /* 59 */
        //        II(ref b, c, d, a, x[k + 13], S44, 0x4e0811a1); /* 60 */
        //        II(ref a, b, c, d, x[k + 4], S41, 0xf7537e82); /* 61 */
        //        II(ref d, a, b, c, x[k + 11], S42, 0xbd3af235); /* 62 */
        //        II(ref c, d, a, b, x[k + 2], S43, 0x2ad7d2bb); /* 63 */
        //        II(ref b, c, d, a, x[k + 9], S44, 0xeb86d391); /* 64 */
        //        A += a;
        //        B += b;
        //        C += c;
        //        D += d;
        //    }
        //    return new UInt32[] { A, B, C, D };
        //}

        //private static byte[] MD5Array(byte[] input)
        //{
        //    MD5_Init();
        //    UInt32[] block = MD5_Append(input);
        //    UInt32[] bits = MD5_Trasform(block);

        //    // Encodes bits (UInt32[]) into output (byte[]). Assumes len is
        //    // a multiple of 4
        //    byte[] output = new byte[bits.Length * 4];
        //    for (int i = 0, j = 0; i < bits.Length; i++, j += 4)
        //    {
        //        output[j] = (byte)(bits[i] & 0xff);
        //        output[j + 1] = (byte)((bits[i] >> 8) & 0xff);
        //        output[j + 2] = (byte)((bits[i] >> 16) & 0xff);
        //        output[j + 3] = (byte)((bits[i] >> 24) & 0xff);
        //    }
        //    return output;
        //}

        #endregion
    }
}